예제 #1
0
    def ingest(self, co, classname=None, code_objects={}, show_asm=None):
        """
        Pick out tokens from an uncompyle6 code object, and transform them,
        returning a list of uncompyle6 Token's.

        The transformations are made to assist the deparsing grammar.
        Specificially:
           -  various types of LOAD_CONST's are categorized in terms of what they load
           -  COME_FROM instructions are added to assist parsing control structures
           -  MAKE_FUNCTION and FUNCTION_CALLS append the number of positional arguments
           -  some EXTENDED_ARGS instructions are removed

        Also, when we encounter certain tokens, we add them to a set which will cause custom
        grammar rules. Specifically, variable arg tokens like MAKE_FUNCTION or BUILD_LIST
        cause specific rules for the specific number of arguments they take.
        """

        if not show_asm:
            show_asm = self.show_asm

        bytecode = self.build_instructions(co)

        # show_asm = 'both'
        if show_asm in ('both', 'before'):
            for instr in bytecode.get_instructions(co):
                print(instr.disassemble())

        # list of tokens/instructions
        tokens = []

        # "customize" is in the process of going away here
        customize = {}

        if self.is_pypy:
            customize['PyPy'] = 0

        # Scan for assertions. Later we will
        # turn 'LOAD_GLOBAL' to 'LOAD_ASSERT'.
        # 'LOAD_ASSERT' is used in assert statements.
        self.load_asserts = set()

        n = len(self.insts)
        for i, inst in enumerate(self.insts):

            # We need to detect the difference between:
            #   raise AssertionError
            #  and
            #   assert ...
            # If we have a JUMP_FORWARD after the
            # RAISE_VARARGS then we have a "raise" statement
            # else we have an "assert" statement.
            if self.version == 3.0:
                # There is a an implied JUMP_IF_TRUE that we are not testing for (yet?) here
                assert_can_follow = inst.opname == 'POP_TOP' and i+1 < n
            else:
                assert_can_follow = inst.opname == 'POP_JUMP_IF_TRUE' and i+1 < n
            if assert_can_follow:
                next_inst = self.insts[i+1]
                if (next_inst.opname == 'LOAD_GLOBAL' and
                    next_inst.argval == 'AssertionError'):
                    if (i + 2 < n and self.insts[i+2].opname.startswith('RAISE_VARARGS')):
                        self.load_asserts.add(next_inst.offset)
                    pass
                pass

        # Get jump targets
        # Format: {target offset: [jump offsets]}
        jump_targets = self.find_jump_targets(show_asm)
        # print("XXX2", jump_targets)

        last_op_was_break = False

        for i, inst in enumerate(self.insts):

            argval = inst.argval
            op     = inst.opcode

            if inst.opname == 'EXTENDED_ARG':
                # FIXME: The EXTENDED_ARG is used to signal annotation
                # parameters
                if (i+1 < n and
                    self.insts[i+1].opcode != self.opc.MAKE_FUNCTION):
                    continue

            if inst.offset in jump_targets:
                jump_idx = 0
                # We want to process COME_FROMs to the same offset to be in *descending*
                # offset order so we have the larger range or biggest instruction interval
                # last. (I think they are sorted in increasing order, but for safety
                # we sort them). That way, specific COME_FROM tags will match up
                # properly. For example, a "loop" with an "if" nested in it should have the
                # "loop" tag last so the grammar rule matches that properly.
                for jump_offset in sorted(jump_targets[inst.offset], reverse=True):
                    come_from_name = 'COME_FROM'
                    opname = self.opname_for_offset(jump_offset)
                    if opname == 'EXTENDED_ARG':
                        j = xdis.next_offset(op, self.opc, jump_offset)
                        opname = self.opname_for_offset(j)

                    if opname.startswith('SETUP_'):
                        come_from_type = opname[len('SETUP_'):]
                        come_from_name = 'COME_FROM_%s' % come_from_type
                        pass
                    elif inst.offset in self.except_targets:
                        come_from_name = 'COME_FROM_EXCEPT_CLAUSE'
                    tokens.append(Token(come_from_name,
                                        jump_offset, repr(jump_offset),
                                        offset='%s_%s' % (inst.offset, jump_idx),
                                        has_arg = True, opc=self.opc))
                    jump_idx += 1
                    pass
                pass
            elif inst.offset in self.else_start:
                end_offset = self.else_start[inst.offset]
                tokens.append(Token('ELSE',
                                    None, repr(end_offset),
                                    offset='%s' % (inst.offset),
                                    has_arg = True, opc=self.opc))

                pass

            pattr  = inst.argrepr
            opname = inst.opname

            if op in self.opc.CONST_OPS:
                const = argval
                if iscode(const):
                    if const.co_name == '<lambda>':
                        assert opname == 'LOAD_CONST'
                        opname = 'LOAD_LAMBDA'
                    elif const.co_name == '<genexpr>':
                        opname = 'LOAD_GENEXPR'
                    elif const.co_name == '<dictcomp>':
                        opname = 'LOAD_DICTCOMP'
                    elif const.co_name == '<setcomp>':
                        opname = 'LOAD_SETCOMP'
                    elif const.co_name == '<listcomp>':
                        opname = 'LOAD_LISTCOMP'
                    # verify() uses 'pattr' for comparison, since 'attr'
                    # now holds Code(const) and thus can not be used
                    # for comparison (todo: think about changing this)
                    # pattr = 'code_object @ 0x%x %s->%s' %\
                    # (id(const), const.co_filename, const.co_name)
                    pattr = '<code_object ' + const.co_name + '>'
                else:
                    if isinstance(inst.arg, int) and inst.arg < len(co.co_consts):
                        argval, _ = _get_const_info(inst.arg, co.co_consts)
                    # Why don't we use _ above for "pattr" rather than "const"?
                    # This *is* a little hoaky, but we have to coordinate with
                    # other parts like n_LOAD_CONST in pysource.py for example.
                    pattr = const
                    pass
            elif opname in ('MAKE_FUNCTION', 'MAKE_CLOSURE'):
                if self.version >= 3.6:
                    # 3.6+ doesn't have MAKE_CLOSURE, so opname == 'MAKE_FUNCTION'
                    flags = argval
                    opname = 'MAKE_FUNCTION_%d' % (flags)
                    attr = []
                    for flag in self.MAKE_FUNCTION_FLAGS:
                        bit = flags & 1
                        attr.append(bit)
                        flags >>= 1
                    attr = attr[:4] # remove last value: attr[5] == False
                else:
                    pos_args, name_pair_args, annotate_args = parse_fn_counts(inst.argval)
                    pattr = ("%d positional, %d keyword pair, %d annotated" %
                                 (pos_args, name_pair_args, annotate_args))
                    if name_pair_args > 0:
                        opname = '%s_N%d' % (opname, name_pair_args)
                        pass
                    if annotate_args > 0:
                        opname = '%s_A_%d' % (opname, annotate_args)
                        pass
                    opname = '%s_%d' % (opname, pos_args)
                    attr = (pos_args, name_pair_args, annotate_args)
                tokens.append(
                    Token(
                        opname = opname,
                        attr = attr,
                        pattr = pattr,
                        offset = inst.offset,
                        linestart = inst.starts_line,
                        op = op,
                        has_arg = inst.has_arg,
                        opc = self.opc
                    )
                )
                continue
            elif op in self.varargs_ops:
                pos_args = argval
                if self.is_pypy and not pos_args and opname == 'BUILD_MAP':
                    opname = 'BUILD_MAP_n'
                else:
                    opname = '%s_%d' % (opname, pos_args)

            elif self.is_pypy and opname == 'JUMP_IF_NOT_DEBUG':
                # The value in the dict is in special cases in semantic actions, such
                # as JUMP_IF_NOT_DEBUG. The value is not used in these cases, so we put
                # in arbitrary value 0.
                customize[opname] = 0
            elif opname == 'UNPACK_EX':
                # FIXME: try with scanner and parser by
                # changing argval
                before_args = argval & 0xFF
                after_args = (argval >> 8) & 0xff
                pattr = "%d before vararg, %d after" % (before_args, after_args)
                argval = (before_args, after_args)
                opname = '%s_%d+%d' % (opname, before_args, after_args)

            elif op == self.opc.JUMP_ABSOLUTE:
                # Further classify JUMP_ABSOLUTE into backward jumps
                # which are used in loops, and "CONTINUE" jumps which
                # may appear in a "continue" statement.  The loop-type
                # and continue-type jumps will help us classify loop
                # boundaries The continue-type jumps help us get
                # "continue" statements with would otherwise be turned
                # into a "pass" statement because JUMPs are sometimes
                # ignored in rules as just boundary overhead. In
                # comprehensions we might sometimes classify JUMP_BACK
                # as CONTINUE, but that's okay since we add a grammar
                # rule for that.
                pattr = argval
                target = self.get_target(inst.offset)
                if target <= inst.offset:
                    next_opname = self.insts[i+1].opname

                    # 'Continue's include jumps to loops that are not
                    # and the end of a block which follow with POP_BLOCK and COME_FROM_LOOP.
                    # If the JUMP_ABSOLUTE is to a FOR_ITER and it is followed by another JUMP_FORWARD
                    # then we'll take it as a "continue".
                    is_continue = (self.insts[self.offset2inst_index[target]]
                                  .opname == 'FOR_ITER'
                                  and self.insts[i+1].opname == 'JUMP_FORWARD')

                    if (is_continue or
                        (inst.offset in self.stmts and (inst.starts_line and
                        next_opname not in self.not_continue_follow))):
                        opname = 'CONTINUE'
                    else:
                        opname = 'JUMP_BACK'
                        # FIXME: this is a hack to catch stuff like:
                        #   if x: continue
                        # the "continue" is not on a new line.
                        # There are other situations where we don't catch
                        # CONTINUE as well.
                        if tokens[-1].kind == 'JUMP_BACK' and tokens[-1].attr <= argval:
                            if tokens[-2].kind == 'BREAK_LOOP':
                                del tokens[-1]
                            else:
                                # intern is used because we are changing the *previous* token
                                tokens[-1].kind = intern('CONTINUE')
                    if last_op_was_break and opname == 'CONTINUE':
                        last_op_was_break = False
                        continue

            # FIXME: go over for Python 3.6+. This is sometimes wrong
            elif op == self.opc.RETURN_VALUE:
                if inst.offset in self.return_end_ifs:
                    opname = 'RETURN_END_IF'

            elif inst.offset in self.load_asserts:
                opname = 'LOAD_ASSERT'

            last_op_was_break = opname == 'BREAK_LOOP'
            tokens.append(
                Token(
                    opname = opname,
                    attr = argval,
                    pattr = pattr,
                    offset = inst.offset,
                    linestart = inst.starts_line,
                    op = op,
                    has_arg = inst.has_arg,
                    opc = self.opc
                    )
                )
            pass

        if show_asm in ('both', 'after'):
            for t in tokens:
                print(t.format(line_prefix='L.'))
            print()
        return tokens, customize
예제 #2
0
    def ingest(self, co, classname=None, code_objects={}, show_asm=None):
        """
        Pick out tokens from an uncompyle6 code object, and transform them,
        returning a list of uncompyle6 'Token's.

        The transformations are made to assist the deparsing grammar.
        Specificially:
           -  various types of LOAD_CONST's are categorized in terms of what they load
           -  COME_FROM instructions are added to assist parsing control structures
           -  MAKE_FUNCTION and FUNCTION_CALLS append the number of positional arguments

        Also, when we encounter certain tokens, we add them to a set which will cause custom
        grammar rules. Specifically, variable arg tokens like MAKE_FUNCTION or BUILD_LIST
        cause specific rules for the specific number of arguments they take.
        """

        show_asm = self.show_asm if not show_asm else show_asm
        # show_asm = 'after'
        if show_asm in ('both', 'before'):
            bytecode = Bytecode(co, self.opc)
            for instr in bytecode.get_instructions(co):
                print(instr._disassemble())

        # Container for tokens
        tokens = []

        customize = {}
        if self.is_pypy:
            customize['PyPy'] = 1

        self.code = array('B', co.co_code)
        self.build_lines_data(co)
        self.build_prev_op()

        bytecode = Bytecode(co, self.opc)

        # FIXME: put as its own method?
        # Scan for assertions. Later we will
        # turn 'LOAD_GLOBAL' to 'LOAD_ASSERT'.
        # 'LOAD_ASSERT' is used in assert statements.
        self.load_asserts = set()
        bs = list(bytecode)
        n = len(bs)
        for i in range(n):
            inst = bs[i]

            # We need to detect the difference between
            # "raise AssertionError" and "assert"
            # If we have a JUMP_FORWARD after the
            # RAISE_VARARGS then we have a "raise" statement
            # else we have an "assert" statement.
            if inst.opname == 'POP_JUMP_IF_TRUE' and i+1 < n:
                next_inst = bs[i+1]
                if (next_inst.opname == 'LOAD_GLOBAL' and
                    next_inst.argval == 'AssertionError'):
                    for j in range(i+2, n):
                        raise_inst = bs[j]
                        if raise_inst.opname.startswith('RAISE_VARARGS'):
                            if j+1 >= n or bs[j+1].opname != 'JUMP_FORWARD':
                                self.load_asserts.add(next_inst.offset)
                                pass
                            break
                    pass
                pass

        # Get jump targets
        # Format: {target offset: [jump offsets]}
        jump_targets = self.find_jump_targets(show_asm)

        for inst in bytecode:

            argval = inst.argval
            if inst.offset in jump_targets:
                jump_idx = 0
                # We want to process COME_FROMs to the same offset to be in *descending*
                # offset order so we have the larger range or biggest instruction interval
                # last. (I think they are sorted in increasing order, but for safety
                # we sort them). That way, specific COME_FROM tags will match up
                # properly. For example, a "loop" with an "if" nested in it should have the
                # "loop" tag last so the grammar rule matches that properly.
                for jump_offset in sorted(jump_targets[inst.offset], reverse=True):
                    come_from_name = 'COME_FROM'
                    opname = self.opName(jump_offset)
                    if opname.startswith('SETUP_'):
                        come_from_type = opname[len('SETUP_'):]
                        come_from_name = 'COME_FROM_%s' % come_from_type
                        pass
                    tokens.append(Token(come_from_name,
                                        None, repr(jump_offset),
                                        offset='%s_%s' % (inst.offset, jump_idx),
                                        has_arg = True, opc=self.opc))
                    jump_idx += 1
                    pass
                pass
            elif inst.offset in self.else_start:
                end_offset = self.else_start[inst.offset]
                tokens.append(Token('ELSE',
                                    None, repr(end_offset),
                                    offset='%s' % (inst.offset),
                                    has_arg = True, opc=self.opc))

                pass

            pattr =  inst.argrepr
            opname = inst.opname
            op = inst.opcode

            if opname in ['LOAD_CONST']:
                const = inst.argval
                if iscode(const):
                    if const.co_name == '<lambda>':
                        opname = 'LOAD_LAMBDA'
                    elif const.co_name == '<genexpr>':
                        opname = 'LOAD_GENEXPR'
                    elif const.co_name == '<dictcomp>':
                        opname = 'LOAD_DICTCOMP'
                    elif const.co_name == '<setcomp>':
                        opname = 'LOAD_SETCOMP'
                    elif const.co_name == '<listcomp>':
                        opname = 'LOAD_LISTCOMP'
                    # verify() uses 'pattr' for comparison, since 'attr'
                    # now holds Code(const) and thus can not be used
                    # for comparison (todo: think about changing this)
                    # pattr = 'code_object @ 0x%x %s->%s' %\
                    # (id(const), const.co_filename, const.co_name)
                    pattr = '<code_object ' + const.co_name + '>'
                else:
                    pattr = const
                    pass
            elif opname in ('MAKE_FUNCTION', 'MAKE_CLOSURE'):
                pos_args, name_pair_args, annotate_args = parse_fn_counts(inst.argval)
                if name_pair_args > 0:
                    opname = '%s_N%d' % (opname, name_pair_args)
                    pass
                if annotate_args > 0:
                    opname = '%s_A_%d' % (opname, annotate_args)
                    pass
                opname = '%s_%d' % (opname, pos_args)
                pattr = ("%d positional, %d keyword pair, %d annotated" %
                             (pos_args, name_pair_args, annotate_args))
                tokens.append(
                    Token(
                        type_ = opname,
                        attr = (pos_args, name_pair_args, annotate_args),
                        pattr = pattr,
                        offset = inst.offset,
                        linestart = inst.starts_line,
                        op = op,
                        has_arg = op_has_argument(op, op3),
                        opc = self.opc
                    )
                )
                continue
            elif op in self.varargs_ops:
                pos_args = inst.argval
                if self.is_pypy and not pos_args and opname == 'BUILD_MAP':
                    opname = 'BUILD_MAP_n'
                else:
                    opname = '%s_%d' % (opname, pos_args)
            elif self.is_pypy and opname in ('CALL_METHOD', 'JUMP_IF_NOT_DEBUG'):
                # The value in the dict is in special cases in semantic actions, such
                # as CALL_FUNCTION. The value is not used in these cases, so we put
                # in arbitrary value 0.
                customize[opname] = 0
            elif opname == 'UNPACK_EX':
                # FIXME: try with scanner and parser by
                # changing inst.argval
                before_args = inst.argval & 0xFF
                after_args = (inst.argval >> 8) & 0xff
                pattr = "%d before vararg, %d after" % (before_args, after_args)
                argval = (before_args, after_args)
                opname = '%s_%d+%d' % (opname, before_args, after_args)

            elif op == self.opc.JUMP_ABSOLUTE:
                # Further classify JUMP_ABSOLUTE into backward jumps
                # which are used in loops, and "CONTINUE" jumps which
                # may appear in a "continue" statement.  The loop-type
                # and continue-type jumps will help us classify loop
                # boundaries The continue-type jumps help us get
                # "continue" statements with would otherwise be turned
                # into a "pass" statement because JUMPs are sometimes
                # ignored in rules as just boundary overhead. In
                # comprehensions we might sometimes classify JUMP_BACK
                # as CONTINUE, but that's okay since we add a grammar
                # rule for that.
                pattr = inst.argval
                target = self.get_target(inst.offset)
                if target <= inst.offset:
                    next_opname = self.opname[self.code[inst.offset+3]]
                    if (inst.offset in self.stmts and
                        next_opname not in ('END_FINALLY', 'POP_BLOCK',
                                            # Python 3.0 only uses POP_TOP
                                            'POP_TOP')
                        and inst.offset not in self.not_continue):
                        opname = 'CONTINUE'
                    else:
                        opname = 'JUMP_BACK'
                        # FIXME: this is a hack to catch stuff like:
                        #   if x: continue
                        # the "continue" is not on a new line.
                        # There are other situations where we don't catch
                        # CONTINUE as well.
                        if tokens[-1].type == 'JUMP_BACK' and tokens[-1].attr <= argval:
                            # intern is used because we are changing the *previous* token
                            tokens[-1].type = intern('CONTINUE')

            elif op == self.opc.RETURN_VALUE:
                if inst.offset in self.return_end_ifs:
                    opname = 'RETURN_END_IF'
            elif inst.offset in self.load_asserts:
                opname = 'LOAD_ASSERT'

            tokens.append(
                Token(
                    type_ = opname,
                    attr = argval,
                    pattr = pattr,
                    offset = inst.offset,
                    linestart = inst.starts_line,
                    op = op,
                    has_arg = (op >= op3.HAVE_ARGUMENT),
                    opc = self.opc
                    )
                )
            pass

        if show_asm in ('both', 'after'):
            for t in tokens:
                print(t)
            print()
        return tokens, customize
예제 #3
0
    def disassemble(self, co, classname=None, code_objects={}, show_asm=None):
        """
        Pick out tokens from an uncompyle6 code object, and transform them,
        returning a list of uncompyle6 'Token's.

        The tranformations are made to assist the deparsing grammar.
        Specificially:
           -  various types of LOAD_CONST's are categorized in terms of what they load
           -  COME_FROM instructions are added to assist parsing control structures
           -  MAKE_FUNCTION and FUNCTION_CALLS append the number of positional arguments

        Also, when we encounter certain tokens, we add them to a set which will cause custom
        grammar rules. Specifically, variable arg tokens like MAKE_FUNCTION or BUILD_LIST
        cause specific rules for the specific number of arguments they take.
        """

        show_asm = self.show_asm if not show_asm else show_asm
        # show_asm = 'both'
        if show_asm in ('both', 'before'):
            bytecode = Bytecode(co, self.opc)
            for instr in bytecode.get_instructions(co):
                print(instr._disassemble())

        # Container for tokens
        tokens = []

        customize = {}
        if self.is_pypy:
            customize['PyPy'] = 1;

        self.code = array('B', co.co_code)
        self.build_lines_data(co)
        self.build_prev_op()

        bytecode = Bytecode(co, self.opc)

        # FIXME: put as its own method?
        # Scan for assertions. Later we will
        # turn 'LOAD_GLOBAL' to 'LOAD_ASSERT'.
        # 'LOAD_ASSERT' is used in assert statements.
        self.load_asserts = set()
        bs = list(bytecode)
        n = len(bs)
        for i in range(n):
            inst = bs[i]

            # We need to detect the difference between
            # "raise AssertionError" and "assert"
            # If we have a JUMP_FORWARD after the
            # RAISE_VARARGS then we have a "raise" statement
            # else we have an "assert" statement.
            if inst.opname == 'POP_JUMP_IF_TRUE' and i+1 < n:
                next_inst = bs[i+1]
                if (next_inst.opname == 'LOAD_GLOBAL' and
                    next_inst.argval == 'AssertionError'):
                    for j in range(i+2, n):
                        raise_inst = bs[j]
                        if raise_inst.opname.startswith('RAISE_VARARGS'):
                            if j+1 >= n or bs[j+1].opname != 'JUMP_FORWARD':
                                self.load_asserts.add(next_inst.offset)
                                pass
                            break
                    pass
                pass

        # Get jump targets
        # Format: {target offset: [jump offsets]}
        jump_targets = self.find_jump_targets()

        for inst in bytecode:

            argval = inst.argval
            if inst.offset in jump_targets:
                jump_idx = 0
                for jump_offset in jump_targets[inst.offset]:
                    tokens.append(Token('COME_FROM', None, repr(jump_offset),
                                        offset='%s_%s' % (inst.offset, jump_idx),
                                        has_arg = True, opc=self.opc))
                    jump_idx += 1
                    pass
                pass

            pattr =  inst.argrepr
            opname = inst.opname
            op = inst.opcode

            if opname in ['LOAD_CONST']:
                const = inst.argval
                if iscode(const):
                    if const.co_name == '<lambda>':
                        opname = 'LOAD_LAMBDA'
                    elif const.co_name == '<genexpr>':
                        opname = 'LOAD_GENEXPR'
                    elif const.co_name == '<dictcomp>':
                        opname = 'LOAD_DICTCOMP'
                    elif const.co_name == '<setcomp>':
                        opname = 'LOAD_SETCOMP'
                    elif const.co_name == '<listcomp>':
                        opname = 'LOAD_LISTCOMP'
                    # verify() uses 'pattr' for comparison, since 'attr'
                    # now holds Code(const) and thus can not be used
                    # for comparison (todo: think about changing this)
                    # pattr = 'code_object @ 0x%x %s->%s' %\
                    # (id(const), const.co_filename, const.co_name)
                    pattr = '<code_object ' + const.co_name + '>'
                else:
                    pattr = const
                    pass
            elif opname in ('MAKE_FUNCTION', 'MAKE_CLOSURE'):
                pos_args, name_pair_args, annotate_args = parse_fn_counts(inst.argval)
                if name_pair_args > 0:
                    opname = '%s_N%d' % (opname, name_pair_args)
                    pass
                if annotate_args > 0:
                    opname = '%s_A_%d' % [opname, annotate_args]
                    pass
                opname = '%s_%d' % (opname, pos_args)
                pattr = ("%d positional, %d keyword pair, %d annotated" %
                             (pos_args, name_pair_args, annotate_args))
                tokens.append(
                    Token(
                        type_ = opname,
                        attr = (pos_args, name_pair_args, annotate_args),
                        pattr = pattr,
                        offset = inst.offset,
                        linestart = inst.starts_line,
                        op = op,
                        has_arg = op_has_argument(op, op3),
                        opc = self.opc
                    )
                )
                continue
            elif op in self.varargs_ops:
                pos_args = inst.argval
                if self.is_pypy and not pos_args and opname == 'BUILD_MAP':
                    opname = 'BUILD_MAP_n'
                else:
                    opname = '%s_%d' % (opname, pos_args)
            elif self.is_pypy and opname in ('CALL_METHOD', 'JUMP_IF_NOT_DEBUG'):
                # The value in the dict is in special cases in semantic actions, such
                # as CALL_FUNCTION. The value is not used in these cases, so we put
                # in arbitrary value 0.
                customize[opname] = 0
            elif opname == 'UNPACK_EX':
                # FIXME: try with scanner and parser by
                # changing inst.argval
                before_args = inst.argval & 0xFF
                after_args = (inst.argval >> 8) & 0xff
                pattr = "%d before vararg, %d after" % (before_args, after_args)
                argval = (before_args, after_args)
                opname = '%s_%d+%d' % (opname, before_args, after_args)
            elif op == self.opc.JUMP_ABSOLUTE:
                # Further classify JUMP_ABSOLUTE into backward jumps
                # which are used in loops, and "CONTINUE" jumps which
                # may appear in a "continue" statement.  The loop-type
                # and continue-type jumps will help us classify loop
                # boundaries The continue-type jumps help us get
                # "continue" statements with would otherwise be turned
                # into a "pass" statement because JUMPs are sometimes
                # ignored in rules as just boundary overhead. In
                # comprehensions we might sometimes classify JUMP_BACK
                # as CONTINUE, but that's okay since we add a grammar
                # rule for that.
                pattr = inst.argval
                target = self.get_target(inst.offset)
                if target <= inst.offset:
                    next_opname = self.opname[self.code[inst.offset+3]]
                    if (inst.offset in self.stmts and
                        next_opname not in ('END_FINALLY', 'POP_BLOCK')
                        and inst.offset not in self.not_continue):
                        opname = 'CONTINUE'
                    else:
                        opname = 'JUMP_BACK'
                        # FIXME: this is a hack to catch stuff like:
                        #   if x: continue
                        # the "continue" is not on a new line.
                        # There are other situations were we don't catch
                        # CONTINUE as well.
                        if tokens[-1].type == 'JUMP_BACK':
                            tokens[-1].type = intern('CONTINUE')

            elif op == self.opc.RETURN_VALUE:
                if inst.offset in self.return_end_ifs:
                    opname = 'RETURN_END_IF'
            elif inst.offset in self.load_asserts:
                opname = 'LOAD_ASSERT'

            tokens.append(
                Token(
                    type_ = opname,
                    attr = argval,
                    pattr = pattr,
                    offset = inst.offset,
                    linestart = inst.starts_line,
                    op = op,
                    has_arg = (op >= op3.HAVE_ARGUMENT),
                    opc = self.opc
                    )
                )
            pass

        if show_asm in ('both', 'after'):
            for t in tokens:
                print(t)
            print()
        return tokens, customize